That Heathrow temperature record ?

The record highest ever recorded July temperature by the Met Office at Heathrow Airport was given huge media coverage. The record was broken during one single heat spike that lasted just over 20 minutes between 14:06 and 14:30. What caused that heat spike? Mark McCarthy argues it was due to a break in clouds, and refutes Paul Homewood’s proposal that a change in wind direction sucked in hot Jet exhausts . However Mark doesn’t explain why a similar sun burst just 30 minutes later produced no temperature response whatsoever. He instead  writes : “In this instance there is no compelling evidence to suggest the measurement is incorrect”. I disagree. There is compelling evidence that such a sharp temperature peak lasting just 20 minutes was actually caused by 3 long haul flights landing in quick succession, then exacerbated by the SE wind direction and late runway exits.

The record was broken during a heat spike that occured between 14:06 and 14:30

The record was broken during a heat spike that occured between 14:06 and 14:30

The weather station is located on the northern border of Heathrow just beyond the North Runway. On July 1st the North runway was being used for landing aircraft arriving from the west because there was an increasing 4 m/s SE wind.  This wind was also blowing directly up a major exit runway lane directly pointing towards the Met station.

Location of the Met Office weather station at Heathrow is shown by the orange icon. The blue arrow shows the wind direction from the SE.

Location of the Met Office weather station at Heathrow is shown by the orange icon. The blue arrow shows the wind direction from the SE.

 

A BA 747-400 originating from San Francisco, a BA 777 from Tokyo and an Etihan A380

Heathrow wind speed July 1st

Heathrow wind speed July 1st

superjumbo all landed within minutes of each other  between ~ 14:00 and ~14:30 on July 1. Smaller aircraft normally exit well before they reach that exit, but  large heavy aircraft need far more runway to stop.  They must exit directly alongside the Met station, and as they turn SE towards the terminals their Jet engines accelerate thereby pumping hot exhausts directly towards the Stephensen screen. The wind directon on July 1 ensured that those hot gases reached the station. This, in my opinion, is a far more likely explanation for the sudden spike in temperature rather than any  short sunny spell. Timings on  plots shown below confirming this are approximate C/O Plane Finder on July 1.

BA 747-400 lands from San Francisco

BA 747-400 lands from San Francisco

Etihad A380 lands on North Runway

Etihad A380 lands on North Runway

Heathrow is neither a registered WMO station nor is it is not one of the ~7300 stations included in CRUTEM4, NCDC GHCN V3 analysis. I am pretty well convinced that the Met Office made a mistake on this one. Did their zeal to find a record July temperature anywhere cloud their judgement? Heathrow  was bound to be contentious because it is one of the world’s busiest and most compact airports. The ‘heat wave’ only lasted one single day so who really cares anyway?  On balance I think Paul Homeward was more likely than not correct in his original analysis.

Correction: Heathrow is a WMO registered site and in CRUTEM4 !

About Clive Best

PhD High Energy Physics Worked at CERN, Rutherford Lab, JET, JRC, OSVision
This entry was posted in Meteorology, UK Met Office and tagged . Bookmark the permalink.

49 Responses to That Heathrow temperature record ?

  1. Andrew Carey says:

    Didn’t know Heathrow not counted as a registered WMO. Fascinating reading, cheers.

  2. Euan Mearns says:

    Clive, the interesting thing about this story is the science psychology. The warmists are desperate to drag up and publicise any fragment of data that may support their “theories”. The same happens on the other side with the solar coolers desperately waiting for a cold catastrophe to befall Britain. I can admit to belonging to that group 🙁

    I am at my cottage in Perthshire, it is late July and we just walked our dogs about 21:00. My wife had hat and gloves on. We have the wood burner on. The outside temperature is 11?C. Why is the MET office not reporting on this?

    The broader question is why did England have a heat wave? Was this because CO2 increased the surface air temperature at Heathrow? Off course not. It is because the sub polar jet is becoming increasingly meandering. This can either draw anomalous cold air southwards from the Arctic or anomalous warm air northwards from the tropics as was the case for England a few weeks ago.

    As for the MET office making a big deal out of that T spike at Heathrow, if indeed they did so, I didn’t consider this story worth any time at all following. Any scientist observing a spike like you show recorded at an extraordinary site like Heathrow would simply discount it as an outlier and should be at pains to explain so in the media. If the MET office have not done this then this is proof positive that they are not scientific.

    • Clive Best says:

      I agree completely. There seems to be a need for warming storylines to gain public support ahead of the Paris meeting. This was just a one day UK heatwave of little significance. I wonder if anyone at the Met Office remembers 1976. We had 2 months of hot sunshine without any rainfall. Temperaures were above 30C every day for nearly a month. The drought was so bad that Cornish houses were asked to flush the toilet only once a day ! That was what I call a real heatwave! Everyone was delighted.

      I have been in Liguria for the past 3 weeks. The temperature is hot and sunny and has reached 34 to 36C every single day, falling to just ~27C at night. In cities like Genova & Milan it reaches 38C and higher, even Italians find it hard to sleep. The sand on the beach is over 50C and it hurts to walk on.

      If I park my car in the sun then temperatures can rise to well over 42C. Once I drive around for 10 minutes the temperaure falls to 34C. Temperatures are supposed to be air temperatures 2m above ground and measured in the shade. Temperature spikes lasting just 20 minutes cannot happen for meteorological reasons. They must have a local cause – either poor shielding or an external heat source.

      Take a look at this interview about the futility of knee-jerk action by any single country. The only long term answer is technical innovation.

      https://youtu.be/ZZ6t7m5RlnQ

    • Ben Vorlich says:

      Euan
      My brother in Dunning is sharing your pain.

      I agree I don’t want to return to the LIA the Minoan Optimum on the other hand would be fine.

  3. Joe Public says:

    Don’t forget jets also use reverse-thrust during landing. This heated air is not only diverted rearwards, but to both sides too.

    In addition, there are multiple planes taxiing beside the main runway(s), waiting to take off.

  4. Joe Public says:

    The Met Office Press Office, in a reply to Paul Homewood, stated:

    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.

    • Clive Best says:

      In that one answer they are admitting that heat ‘reflected’ from the ground is the most likely cause of the spike. Hot exhaust gases reaching the station is another. If they just want mixing – then instal a fan !

  5. Nick Stokes says:

    Heathrow on the day reached 36.7C, which is 98.06F. Some other temperatures around, according to Accuweather:
    St Albans 98F
    Aylesbury 98F
    Reading 98F
    Windsor 98F
    Doesn’t look like Heathrow needs all this special pleading.

    • Nick Stokes says:

      TonyB pointed out at WUWT that Accuweather seems to just use Heathrow temperatures in the data for nearby towns, and that in Reading at least, the temperature reached only about 93F. So this isn’t useful data – apologies.

  6. Cytokinin says:

    Why is it that weather becomes climate in so much of the media. Why are record highs reported, but but record lows ignored. In the north Scottish highlands we have experienced the cpressureay and June on record and if things continue, it will be the coldest July too. In Orkney farmers are having to sell cattle because it has been so cold that the grass hasn’t grown. There is still snow on the hills in mid July, normally all gone in May. Further afield there is cold, with record snow falls in south Norway in early June. The last of the snow only disappeared in Boston USA this week. Sydney Australia had snow last week! This all does not imply global warming, or global cooling. It is merely fluctuations in weather, which has always happened. The media however likes hottest day stories, flood stories, big wind stories and hopefully a few deaths. It sells papers and increases viewing and so brings in more revenue. Why the BBC behave like this is a mystery unless they feel their publicly funded service has to out sensationalise the rest of the media.

    Understanding the drivers of climate is only clouded by sensationalism, since fear created by the media leads to demands for action and gets in the way of good objective scientific analysis. Science cannot be done to time scale and turns into politics if put under pressure.

    1.30pm and the outside temperature is 13C, 10 degrees lower than this time last year.

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  8. Clive

    Are the flight arrival times GMT or BST (The Met graph is GMT)?

    i.e the temp spike was 14.15GMT, which is 15.15 BST.

    • Clive Best says:

      Paul,

      I had a twitter exchange with Mark McCarthy about just this point. It is quite likely that I am an hour out so I will need to recheck the arrivals times. I am using an Ipad APP ‘Plane Finder’ while in Italy !

      My theory is simple. A large aircraft exited down that exit lane with a SE wind. As it turns to accelerate so hot exhausts are blown back onto the weather station ~50m away. The SE wind also ensured the heat pulse reached the station.

      I now need to double check whether this is correlated in exact time.

  9. From the ORIGINAL CO2 MOLESTER, Prof. Hubert Lamb; who was promoting ”Big Ice Age for year 2000, because of CO2 DIMMING EFFECT”

    MOST of the ”ICE AGE for year 200 Predictors” are now in the Warmist Cult:

    Here’s a list of articles from the 70’s predicting the next ice age along with a link to the website that listed them.
    1970 – Colder Winters Held Dawn of New Ice Age – Scientists See Ice Age In the Future (The Washington Post, January 11, 1970)
    1970 – Is Mankind Manufacturing a New Ice Age for Itself? (L.A. Times, January 15, 1970)
    1970 – New Ice Age May Descend On Man (Sumter Daily Item, January 26, 1970)
    1970 – Pollution Prospect A Chilling One (The Argus-Press, January 26, 1970)
    1970 – Pollution’s 2-way ‘Freeze’ On Society (Middlesboro Daily News, January 28, 1970)
    1970 – Cold Facts About Pollution (The Southeast Missourian, January 29, 1970)
    1970 – Pollution Could Cause Ice Age, Agency Reports (St. Petersburg Times, March 4, 1970)
    1970 – Scientist predicts a new ice age by 21st century (The Boston Globe, April 16, 1970)
    1970 – Pollution Called Ice Age Threat (St. Petersburg Times, June 26, 1970)
    1970 – U.S. and Soviet Press Studies of a Colder Arctic (The New York Times, July 18, 1970)
    1970 – Dirt Will Bring New Ice Age (The Sydney Morning Herald, October 19, 1970)
    1971 – Ice Age Refugee Dies Underground (Montreal Gazette, Febuary 17, 1971)
    1971 – Pollution Might Lead To Another Ice Age (The Schenectady Gazette, March 22, 1971)
    1971 – Pollution May Bring Ice Age – Scientist Rites Risk (The Windsor Star, March 23, 1971)
    1971 – U.S. Scientist Sees New Ice Age Coming (The Washington Post, July 9, 1971)
    1971 – Ice Age Around the Corner (Chicago Tribune, July 10, 1971)
    1971 – New Ice Age Coming – It’s Already Getting Colder (L.A. Times, October 24, 1971)
    1971 – Another Ice Age? Pollution Blocking Sunlight (The Day, November 1, 1971)
    1971 – Air Pollution Could Bring An Ice Age (Harlan Daily Enterprise, November 4, 1971)
    1972 – Air pollution may cause ice age (Free-Lance Star, February 3, 1972)
    1972 – Scientist Says New ice Age Coming (The Ledger, February 13, 1972)
    1972 – Ice Age Cometh For Dicey Times (The Sun, May 29, 1972)
    1972 – Ice Age Coming (Deseret News, September 8, 1972)
    1972 – There’s a new Ice Age coming! (The Windsor Star, September 9, 1972)
    1972 – Scientist predicts new ice age (Free-Lance Star, September 11, 1972)
    1972 – British Expert on Climate Change Says New Ice Age Creeping Over Northern Hemisphere (Lewiston Evening Journal, September 11, 1972)
    1972 – Climate Seen Cooling For Return Of Ice Age (The Portsmouth Times, ?September 11, 1972?)
    1972 – New Ice Age Slipping Over North (The Press-Courier, September 11, 1972)
    1972 – Beginning of new ice age (The Canberra Times, September 12, 1972)
    1972 – Ice Age Begins A New Assault In North (The Age, September 12, 1972)
    1972 – Weather To Get Colder (Montreal Gazette, ?September 12, 1972?)
    1972 – British climate expert predicts new Ice Age (The Christian Science Monitor, September 23, 1972)
    1972 – Scientist Sees Chilling Signs of New Ice Age (L.A. Times, September 24, 1972)
    1972 – Science: Another Ice Age? (Time Magazine, November 13, 1972)
    1972 – Geologist at Case Traces Long Winters – Sees Ice Age in 20 Years (Youngstown Vindicator, December 13, 1972)
    1972 – Ice Age On Its Way, Scientist Says (Toledo Blade, December 13, 1972)
    1972 – Ice Age Predicted In About 200 Years (The Portsmouth Times, December 14, 1972)
    1973 – New Ice Age coming? (Popular Science, January 1973)
    1973 – The Ice Age Cometh (The Saturday Review, March 24, 1973)
    1973 – Believe new ice age is coming (The Bryan Times, March 31, 1973)
    1973 – ‘Man-made Ice Age’ Worries Scientists (The Free Lance-Star, June 22, 1973)
    1973 – Fear Of Man-made Ice Age (The Spartanburg Herald, June 28, 1973)
    1973 – Possibility Of Ice Age Worries The Scientists (The Argus-Press, November 12, 1973)
    1973 – Weather-watchers think another ice age may be on the way (The Christian Science Monitor, December 11, 1973)
    1974 – Ominous Changes in the World’s Weather (PDF) (Fortune Magazine, February 1974)
    1974 – Atmospheric Dirt: Ice Age Coming?? (Pittsburgh Press, February 28, 1974)
    1974 – Support for theory of a cooling world (The Canberra Times, May 16, 1974)
    1974 – New evidence indicates ice age here (Eugene Register-Guard, May 29, 1974)
    1974 – Another Ice Age? (Time Magazine, June 24, 1974)
    1974 – 2 Scientists Think ‘Little’ Ice Age Near (Hartford Courant, August 11, 1974)
    1974 – Ice Age, worse food crisis seen (Chicago Tribune, October 30, 1974)
    1974 – Imminent Arrival of the Ice (Radio Times, November 14, 1974)
    1974 – Making a BBC Science Special [The Weather Machine] (New Scientist, November 14, 1974)
    1974 – The Weather Machine (BBC, November 20, 1974)
    1974 – New ice age ‘could be in our lifetime’ (The Canberra Times, November 22, 1974)
    1974 – Believes Pollution Could Bring On Ice Age (Ludington Daily News, December 4, 1974)
    1974 – Pollution Could Spur Ice Age, Nasa Says (Beaver Country Times, ?December 4, 1974?)
    1974 – Air Pollution May Trigger Ice Age, Scientists Feel (The Telegraph, ?December 5, 1974?)
    1974 – More Air Pollution Could Trigger Ice Age Disaster (Daily Sentinel, ?December 5, 1974?)
    1974 – Scientists Fear Smog Could Cause Ice Age (Milwaukee Journal Sentinel, December 5, 1974)
    1975 – Climate Changes Called Ominous (The New York Times, January 19, 1975)
    1975 – Climate Change: Chilling Possibilities (Science News, March 1, 1975)
    1975 – B-r-r-r-r: New Ice Age on way soon? (Chicago Tribune, March 2, 1975)
    1975 – Cooling Trends Arouse Fear That New Ice Age Coming (Eugene Register-Guard, ?March 2, 1975?)
    1975 – Is Another Ice Age Due? Arctic Ice Expands In Last Decade (Youngstown Vindicator, ?March 2, 1975?)
    1975 – Is Earth Headed For Another Ice Age? (Reading Eagle, March 2, 1975)
    1975 – New Ice Age Dawning? Significant Shift In Climate Seen (Times Daily, ?March 2, 1975?)
    1975 – There’s Troublesome Weather Ahead (Tri City Herald, ?March 2, 1975?)
    1975 – Is Earth Doomed To Live Through Another Ice Age? (The Robesonian, ?March 3, 1975?)
    1975 – The Ice Age cometh: the system that controls our climate (Chicago Tribune, April 13, 1975)
    1975 – The Cooling World (Newsweek, April 28, 1975)
    1975 – Cooling trend may signal coming of another Ice Age (The Sun, May 16, 1975)
    1975 – Scientists Ask Why World Climate Is Changing; Major Cooling May Be Ahead (PDF) (The New York Times, May 21, 1975)
    1975 – Summer of A New Ice Age (The Age, June 5, 1975)
    1975 – In the Grip of a New Ice Age? (International Wildlife, July-August, 1975)
    1975 – Experts ponder another ice age (The Spokesman-Review, September 8, 1975)
    1975 – Oil Spill Could Cause New Ice Age (Milwaukee Journal Sentinel, December 11, 1975)
    1976 – Deadly Harvest [Film] (Starring: Kim Cattrall, Clint Walker, 1976)
    1976 – The Cooling: Has the Next Ice Age Already Begun? [Book] (Lowell Ponte, 1976)
    1976 – Ice Age Predicted (Reading Eagle, January 22, 1976)
    1976 – Ice Age Predicted In Century (Bangor Daily News, January 22, 1976)
    1976 – It’s Going To Get Chilly About 125 Years From Now (Sarasota Herald-Tribune, January 23, 1976)
    1976 – Worrisome CIA Report; Even U.S. Farms May be Hit by Cooling Trend (U.S. News & World Report, May 31, 1976)
    1977 – Blizzard – What Happens if it Doesn’t Stop? [Book] (George Stone, 1977)
    1977 – The Weather Conspiracy: The Coming of the New Ice Age [Book] (The Impact Team, 1977)
    1977 – The Ice Age Cometh… (New York Magazine, January 31, 1977)
    1977 – The Big Freeze (Time Magazine, January 31, 1977)
    1977 – Has The Ice Age Cometh Again? (Calgary Herald, February 1, 1977)
    1977 – Space Mirrors Proposed To Prevent Crop Freezes (Bangor Daily News, February 7, 1977)
    1977 – We Will Freeze in the Dark (Capital Cities Communications Documentary, Host: Nancy Dickerson, April 12, 1977)
    1978 – Ice! [Book] (Arnold Federbush, 1978)
    1978 – The New Ice Age [Book] (Henry Gilfond, 1978)
    1978 – Winter May Be Colder Than In Last Ice Age (Deseret News, January 2, 1978)
    1978 – Current Winters Seen Colder Than In Ice Age? (The Telegraph, January 3, 1978)
    1978 – Winter Temperatures Colder Than Last Ice Age (Eugene Register-Guard, Eugene Register-Guard, January 3, 1978)
    1978 – International Team of Specialists Finds No End in Sight to 30-Year Cooling Trend in Northern Hemisphere (The New York Times, January 5, 1978)
    1978 – Little Ice Age: Severe winters and cool summers ahead (Calgary Herald, January 10, 1978)
    1978 – Winters Will Get Colder, ‘we’re Entering Little Ice Age’ (Daily Record, January 10, 1978)
    1978 – Geologist Says Winters Getting Colder (Middlesboro Daily News, January 16, 1978)
    1978 – It’s Going To Get Colder (Boca Raton News, ?January 17, 1978?)
    1978 – Another Ice Age? (Kentucky New Era, February 12, 1978)
    1978 – Another Ice Age? (Reading Eagle, ?February 13, 1978?)
    1978 – The Coming Ice Age (In Search Of TV Show, Season 2, Episode 23, Host: Leonard Nimoy, May 1978)
    1978 – An Ice Age Is Coming Weather Expert Fears (Milwaukee Sentinel, November 17, 1978)
    1979 – A Choice of Catastrophes – The Disasters That Threaten Our World [Book] (Isaac Asimov, 1979)
    1979 – The Sixth Winter [Book] (John R. Gribbin, 1979)
    1979 – The New Ice Age Cometh (The Age, January 16, 1979)
    1979 – Ice Age Building Up (Daily Record, June 5, 1979)
    1979 – Large Glacial Buildup Could Mean Ice Age (Daily Chronicle, June 5, 1979)
    1979 – Ice Age On Its Way (Lewiston Morning Tribune, June 7, 1979)
    1979 – Get Ready to Freeze (Daily Chronicle, October 12, 1979)
    1979 – New ice age almost upon us? (The Christian Science Monitor, November 14, 1979)
    * Note: A couple of the news stories are duplicates in different papers with slightly different titles, this is intentional to show that these types of stories were not isolated to a certain regional paper.
    http://www.populartechnology.net/2013/02/the-1970s-global-cooling-alarmism.html

  10. Ben Vorlich says:

    Not doubting your landing information, I wondered where you found it?

    I looked here
    http://www.lhr-lgw.co.uk/lhr%20jul%202015.html

    earlier in the week and I don’t understand all the columns but it identifies a flight number, registration number, a plane type and a runway (L or R not sure about this?). Checking I couldn’t find any A380s in the time frame, two in quick succession I don’t know whether the times are for arrival/departure from the terminal in which case the time on the runway would be several minutes before or after.
    14:31 Qatar Airways on R
    14:34 Singapore Airlines on R
    747 also a couple
    1408 BA on L ( Peking?)
    1415 BA on L ( Las Vegas)

    Quite a lot of B777, B787, A320, A330

    This is purely guesswork on my part so it could be horribly wrong,

    Thanks

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  12. Dave Ward says:

    @ Ben – I understand from my sources that until 7:30pm the North runway (“L” or left as a pilot would see it) was used for landings, and the South (“R”) for take-offs. From the link you provided I can see the change to runway 27 occurring between “1831” & “1833” which means times in that list are shown in GMT. This is standard aviation practice, so we would need to be looking for times in the 1300 range. I used “CTRL+F” to highlight all the “09L” entries, and as it happens, there were TWO B747-400’s in succession, at 1314 & 1315 respectively. That ought to have generated a good blast of heat!

    • Ben Vorlich says:

      Thank you Dave that makes good sense. I’m not familiar with the world of aviation and how the log times.

      Now I know that I can see that the planes landing (09L)
      13:14 BOEING 747-436
      13:15 BOEING 747-436
      13:18 BOEING 747-436
      So three 747 landings in 4-5 minutes. As you say a large blast of heat with with a lot of A320s to keep things nicely warm.

      BTW you can search for details on British registered planes here
      https://www.caa.co.uk/application.aspx?catid=60&pagetype=65&appid=1
      and the three are powered by
      13:14 4 x ROLLS-ROYCE RB211-524G2-T-19
      13:15: 4 x ROLLS-ROYCE RB211-524G2-19
      13:18: 4 x ROLLS-ROYCE RB211-524G2-19

    • Clive Best says:

      Thanks Dave and Ben ! That is a great source (even though I had to use a text editer to read it).

      The heat spike occured more or less exactly at 14:15 GMT. Two BA 747-400s landed within 2 minues of each other at precisely the right time. The first BA 272 from San Diego landed at 14:13 GMT and the second BA 274 from Las Vegas landed at 14:15 GMT. It is likely that such heavy aircraft would have had to exit the runway directly in-line with the Met Office station. That equates to 8 Rolls Royce Jet engines pointing directly at the station within a 2 minute period. This was then enhanced by a SE wind of 12 M/s blowing directly down the exit lane towards the station.

      It is inconceivable to me that the Met Office can argue that a simple break in the clouds could cause such a huge temperaure spike. The Stephensen screens are supposed to be shade the thermometers from the sun! However they have air vents to let air circulate inside !

      • Dave Ward says:

        @Clive – the “mht” file that you get from Ben Vorlich’s link above showed up (to me) as an”IE” document. Since I don’t use IE, I right clicked on the saved file and selected “Open with Palemoon” (a Firefox variant) and it opened in a normal tab, from where I was able to use “Ctrl+F” to highlight the appropriate entries.

        Further to the aircraft movements – since smaller planes would normally exit the runway as soon as they have their speed under control, there would (in all probability) be a number of them on the parallel taxiway, in addition to the “heavies” which would use most of the landing distance available. From watching Flightradar24, it’s clear that the vast majority of aircraft go to and from stands at the Eastern end of the site, so the smaller A320’s ~ B737’s etc may well have to stop before the relevant turn off, wait for the “heavies” to cross, and then apply some power to get moving again. To aid turning it’s usual for pilots to apply differential power, which in this situation would mean advancing the port (left) engine(s) more, so any heat resulting would be correspondingly closer to the met station…

  13. pdtillman says:

    Just a xref to Willis Eschenbach’s similar analysis:
    http://wattsupwiththat.com/2015/07/18/heathrow-hijinks/

    Here, as elsewhere, one senses a whiff of desperation, as Nature fails to stick to the CAGW Party Line….

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  15. Bryce Payne says:

    Climate and climate change are long term, extremely complex subjects. If GHGs are causing a temperature change it will appear as the cumulative effect of many minute ripples on top of larger waves. None of them will be apparent at the time, but the effect may accumulate eventually.
    The Heathrow heat spike in question was obviously an anomaly, and its occurrence does not speak either for or against climate change. So much noise from what should have been an unreported anomaly. Its occurrence raises the further question of how long has that station been affected by more dilute jet wash in general? There could be substantial unrecognized effects in the historical data from that station. Why was that met station not moved long ago? Might be interesting to look at aviation history with respect to large jets, and trends in historical temperature at airports, or at Heathrow anyway.

    • bob Peckham says:

      Not to mention the gradually increasing heat island effect of more asphalt, concrete, terminals and car parks on a time scale of decades. Not to mention the gradually expanding heat island of London itself, also on a timescale of decades.

      • Clive Best says:

        Bob,

        Remember that warming is always measured in temperature anomalies whereas temperature records are measured in degrees centigrade. That way the Urban Heat effect can simultaneously break temperature records and be proven not to effect global warming. How is that possible? The trick is to renormalise anomalies for each station to average temperature values just 20 years ago.

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  17. climanrecon says:

    One upside for me of the demise of GHCN is the discovery of the GSOD data set of daily met numbers, produced by NOAA. By a great stroke of luck there is GSOD data for both Heathrow, and for nearby (6 miles away) RAF Northolt. I find OGIMET to be a great way to access small amounts of GSOD data. Maximum temperatures on 1st July 2015 were:

    Heathrow: 36.7C
    Northolt: 35.7C

    One would have to assess the overall relative temperature differences between the sites, but the figures above suggest to me that not a lot of the Heathrow figure can be ascribed to aircraft.

  18. John L Ryan says:

    Why no scale on your maps

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