Guest Post by Willis Eschenbach
Once again the Week In Review-Science Edition over at Dr. Judith Curry’s website brings up interesting news. It appears that the first of July was hot in the UK, and among others the airport at Heathrow set a record high temperature for the date.. This led to a bit of a flap over in the land of the Anglo-Saxophones.
The British newspaper The Telegraph said that they thought the record was bogus. They theorized that it was caused by jet exhaust and wind changes, which seems quite reasonable to me. In response, the Met Office swung into action and posted up a page on their “Carbon Sense” blog saying that no, it was a break in the clouds that did it, the extra sun raised the temperature. Here’s their money graph:
Figure 1. Graph of solar radiation and temperature at Heathrow for the hottest hour on July 1, 2015
They used this graph to claim that it’s the sun, stupid … but the first problem is, according to their graph, about twenty minutes after the peak in temperature, the clouds parted a bit and the solar input jumped up again to nearly as high as it had gone before … but the temperature didn’t change in the slightest. Well, that’s not entirely true. The second time the sun strength increased, the temperature went down. If the temperature spike early in the record were from the sun, does it make sense to you that a subsequent solar spike twenty minutes later would lead to no warming at all?
The second problem is that the sun strength stayed high, but the temperature started dropping before the succeeding decrease in sun strength.
In any case, they kindly provided the data used in the graph, kudos to them for that, plus the wind direction and strength data so we could see that it’s the sun, stupid … except for one detail. They are using that graph and data to claim that it is the sun, not the wind direction as claimed by the Telegraph, that caused the temperature spike.
With the data we can see that the third problem with their claim is that, for at least this short period, the correlation of temperature with wind direction (0.63) was 50% stronger than the correlation of temperature with sunshine (0.42). So their own data, specially provided to back up their claims, actually disagrees with their claims.
Of course, this means nothing about the longer term. However, for the short-term period around the temperature spike, they certainly have not established their case, so we’re still left with the question of what caused the temperature peak.
Some insight into this question comes from the UK Met Office. They’ve kindly provided these examples of the highest record-setting temperatures in the UK on the first of July, 2015 (see the 7 July 2015 entry here )
Figure 2. Highest temperature records set on the first of July, 2015
Now, looking at Figure 2 we have two possibilities. Either a) human actions are increasing the surface air temperatures recorded at Heathrow, or b) by an astounding historical coincidence, the UK’s largest airport was built precisely on top of the warmest spot on the island … I’m going with a) myself, although YMMV.
So being an inquisitive type of fellow, I decided to take a back-of-the-envelope look at just how much actual thermal energy is released at Heathrow. This doesn’t include the heating effect of all those square metres of runway asphalt, but it’s a start.
A bit of research shows the CO2 released at Heathrow by the actual burning of fuel on the ground and in takeoff and landing (under 3,000 feet [900 m] elevation) is about 1.6 million tonnes of CO2/year. Most of this is in the form of jet fuel, which sounds all high-techy but which is actually kerosene.
Using the conversion factor for kerosene of 71.5 kg of CO2 per gigajoule of energy, this converts to 2.24E+16 joules/year, or 6.13E+13 joules per day, of heat solely from the burning of the fuel.
Now, how much would this release of energy warm the air? Well … how much air are we considering? Heathrow covers a large area, 1227 hectares. So let’s figure the air above Heathrow up to the 3,000 feet elevation under which they’re counting the CO2 emitted.. That’s about 1.12E+10 cubic metres of air, or about 1.43E+10 kg of air.
The specific heat of air is easy, it’s about 1 kilojoule per kilogram per degree C. And we can probably figure that about 30% of the energy is used to produce mechanical work, with the rest lost as heat.
So, imagine that we could put a transparent air-tight dome over Heathrow 3,000 feet (900 m) tall, and one day we burned 6.13E+13 joules worth of kerosene inside the dome, and 70% of that energy went into heat … how much would that raise the air temperature?
Short answer? It would give about a 3°C temperature rise, which is 5.4°F.
Now, of course as soon as the air is warmed by jet exhaust it starts rising, and the heat moves constantly upwards and outwards and cool air mixes in at the bottom, so there is no average 3°C temperature rise on the surface.
But obviously, looking at Figure 2, including warming from all sources there is something like a degree or so of peak temperature increase from the urban heat island at Heathrow.
What is this from? While some is from the acres of hot asphalt runways cooking in the sun, in part it’s from the actual burning of the fuel. Have you ever been caught by the blast from a jumbo jet, even from far away? I have, many times. It smells like kerosene, and it’s warmer than the surrounding air, sometimes much warmer. When one of these blasts hits you, you can easily feel the difference in temperature … and so can the airport thermometer.
With that in mind we can see how desperate the UK Met Office is in their defense of the record. Consider this quote from Dr Mark McCarthy, head of the Met Office’s National Climate Information Centre:
Nor does it make sense to think that a passing breeze could have carried a waft of heat from a nearby aircraft, as Homewood suggests. McCarthy tells Carbon Brief:
“We have checked with [air traffic control] 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.”
Had passing aircraft generated turbulence, that would help mix the air close to the ground. This would be more likely to lower the air temperature than raise it, McCarthy says.
I fear Dr. McCarthy has not spent enough time out on the tarmac … first, after landing jets do not have “idle engines”. They use their engines to move around the airport, blowing hot air out behind them as they go. And every time they stop, it takes a big blast of hot air to get them moving again. And second, while it is possible for jets to reduce the ground temperature because of the turbulence from their wings, in general, guess what?
Burning about a million gallons (3.4 million litres) of kerosene per day in one location generally does NOT lower the air temperature as McCarthy implies.
Here’s part of the problem. This shows the location of the meteorological station at Heathrow.
Figure 3. Location of the meteorological station at Heathrow Airport is shown by the white circle. The large runway across the middle is the “north runway” referred to by Dr. McCarthy in the quote above. Note the jet at the bottom for scale.
As you can see, the met station is about 150 metres (500 feet) from the north runway. The difficulty comes after landing and slowing down, when the jets turn off of the eastern end of the runway by the met station on one of the side taxiways. At times in that process, their jet exhaust will be pointed directly at the temperature measuring station. Indeed, when jets turn off on either of the two right-hand taxiways in the picture above, their jet exhaust is pointed directly at the met station for the entire trip down the taxiway … and did I mention that the wind was from the south and southeast during the time of the temperature record, blowing from the taxiways towards the met station?
So … did jet exhaust cause the large spike in Heathrow temperatures on 1 July 2015 that created the new record? I’d say:
a) we don’t know, although it certainly seems plausible and winds were in the right direction, and
b) it certainly can’t be ruled out by what the Met Office has shown, but in any case
c) it doesn’t really matter because jet fuel and runway tarmac assuredly warms Heathrow in general, so any Heathrow records are not very reliable or meaningful.
One final thought for you. Heathrow proudly proclaims that from 2012 to 2013 it decreased its CO2 emissions by 11,923 tonnes of CO2. Cue the applause.
However, during the same period, China increased its emission rate by 358,304,399 tonnes/year of CO2. This means that the increase in Chinese CO2 emissions, not the amount of the emissions themselves but the amount of the increase in emissions, is about 40,874 tonnes per hour… which means that all of Heathrow’s proud one-year accomplishment of emission decreases during all of 2012 was wiped out by China in the first 17 minutes after midnight on January 1, 2012.
Dust in the wind …
Regards to all,
w.
As You May Know: If you disagree with someone, please quote the exact words you disagree with so we can all understand the nature of your objection.
Heathrow Airport Details: Over at the Talkshop, tchannon has a good description of the physical layout of the airport here.
Update from the Comments: First, a number of folks mentioned thrust reversers, which I’d forgotten to consider, and the fact that they blow the warm jet exhaust to the sides … in other words towards the met office.
Also, someone talked of the importance of winds. This is very true.
Wind is indeed important, at times crucial. And even if the speed is constant, the direction can be critical. I was going to include the following but the post was getting long. Another example of met office guys not getting out enough.
Now, any swabbie sailor like myself would look at that and say “Yep, that wind is swinging quite a bit”. It looks pretty typical for a wind regime, the wind direction tends to sway from one side to the other once or twice in an hour or so, which this does.
How much is it swinging? Well, it swings from a minimum of 130° (about southeast) to a maximum of 180° (south) during the hour. This is a not insignificant range of no less than fifty degrees.
And the largest rate of swing was a change of fifteen degrees in five minutes … so I’d have to disagree with Dr. McCarthy when he says:
“We’ve looked at wind data and there is no sudden change in wind direction at Heathrow around the time of the record.”
All the best to you all,
w.
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Also in UK Met Office list of record temperature locations for July 1st are:
Wittering (Royal Air Force (RAF) base – nice tarmac and planes etc.)
Cranwell (RAF training base – nice tarmac and planes etc.)
Manston (airport – formerly RAF Manston – nice tarmac and planes etc )
Marham (RAF base – nice tarmac and planes etc. regularly achieves high records)
Waddington (RAF base – nice tarmac…. you get the picture by now)
Like Willis I have the choice to believe that these location were fortuitously built in five of the hottest spots in the UK, or that acres of tarmac and jet exhaust have more to do with it.
I favour the latter explanation.
Snap. Simultaneous posts 😀
Andy, I’m with you…
MET likes to claim all things are the same….Heathrow just resurfaced that north runway and tarmac with brand new black asphalt….check the link I Posted above this
Quick caveat – Waddington’s runway is in re-build just now, so not much traffic apart from dump trucks, etc. But it has been exceptionally warm in the UK East Midlands on several days this summer.
In which case the Waddington station may well have large dump trucks driving straight past it on a regular basis at the moment!
Quite so. And then, having picked your overheated location, you just have to apply the usual sleight of hand: locate the hottest minute and declare the hottest day.
There are two hot spots in this part of Universe often quoted as the highest temperature record holders of the day, Heathrow airport and Wisley Gardens in Surrey. I am well familiar with both. Heathrow airport can be discounted for obvious reasons, so to some extent RHS Wisley due to its location near the A3 and M25 junction, the two busiest roads in the SE England.
I suspect that you are very generous in assuming 30% of the fuel energy went into work instead of heat. My guess would be that the only energy that left that immediate area left in kinetic energy in the aircraft due to an increase in speed and potential energy due to change in altitude. All of the rest would be turbulence which would quickly be dissipated into heat. While I am not usually shy about making wild guesses, I would not want to even attempt an estimate of kinetic and potential energy of the departing aircraft. Also consider that arriving aircraft may also have some kinetic and potential energy to dissipate. I can’t think of anywhere else it can go except to turbulence and then to heat unless you want to consider how much might actually be accounted for in the deterioration of the tires during braking. The energy dissipated by the brakes also goes directly to heat, but that would take a number of minutes to show up in the atmosphere.
The energy dissipated during the mechanical braking of aircraft arriving at Heathrow is not that much relative to that released from burning fuel. We can easily estimate its order-of-magnitude by assuming an Airbus A320-200 represents a good average of aircraft size between the jumbos and smaller “regional” jets using Heathrow. My apologies, but I’m going to use English units (in honor of our British friends . . . even though they’ve “gone metric”) but will give metric units as well for the bottom line energy dissipation. The A320-200 has a maximum zero-fuel weight of about 138,000 lbm and an operating empty weight of about 94,000 lbm . . . let’s assume with full passenger load, luggage and cargo, and 25% or less fuel load, we have about 140,000 lbm landing. This aircraft has a typical landing speed in the range of 150-160 mph, so let’s assume 155 mph, or 227 ft/sec. This is equivalent to a single A320-200 landing kinetic energy of 1.12E+8 ft-lbf (152 MJ). It is difficult to find information on the fraction of aircraft landing breaking actually performed just by thrust reversers—and note that they are not used on all aircraft—but one source indicates they might provide something in the range of 10-15% of total breaking under normal conditions . . . let’s conservatively use 15%. In 2014, Heathrow had a daily average of 1,290 “air transport movements”. So, these last two figures combine to yield an estimated total mechanical breaking energy dissipation of 1.23E+11 ft-lbf (1.67E+11 joules) per day. Thus, in comparison to to the above article’s estimate of “… 6.13E+13 joules per day, of heat solely from the burning of the fuel”, aircraft landing breaking heat is a small very small fraction.
If the thermometer is primarily used to report airfield conditions it is better if it reports the highest temperature at the airport for pilots to calculate their safety margins. Hot air is less dense and that affects lift and thrust.. It is not therefore suitable as a met station. IF the met office is using it as input to temperature records, that’s just plain wrong. You wouldn’t do it except as a means of deception. Which they know well, better than this Oxfordshire housewife.
Maybe they like to put airports where the air is hottest and hence the least dense?
Cuts down on drag.
Oh, sure, it reduces lift as well, but you cannot have everything.
Tarmac hotter than unpaved countryside?
Where is the evidence for that?
http://mentalfloss.com/sites/default/legacy/blogs/wp-content/uploads/2012/04/LAX_Terminals-565×376.jpg
http://media-cache-ak0.pinimg.com/736x/19/53/b6/1953b635826f59dd01ad5af327fdcb77.jpg
Nope, hot conditions require a longer takeoff run. Air density is the most important factor.
When the air is less dense you can consider the runway as shortened. Those slats and elaborate flaps would be less needed with denser air. It is true in cruise you want less dense air up to a point. Most pilots operating near an airport want the ability to go upwards quickly. Dense air helps with that.
As a child, you never experienced walking barefoot in the summer on a paved road or sidewalk (of any material), dirt, and grass? How sad. Don’t let colors fool you. Black tarred roads and white sand would both burn far worse than brown dirt. More significantly, you could feel the heat radiating up from the roads and the sand, but not the dirt.
I suppose it is never obvious enough to leave off the /sarc tag.
I spend a lot of time walking around barefoot. Always have, since a lad.
I have burned my feet plenty of times. I can recall walking home from the swim club in Philly in summer in bare feet, and halfway across one of the blacktop streets having to run to a white stripe on the road to avoid third degree burns. The pebble-topped concrete of Center City sidewalks is almost never too hot to walk on, although newer and flatter concrete sometimes was. The beaches from Seaside Heights to Cape May were often hot enough to burn the feet, but relief could be had by stopping and pushing aside the top few inches to reach the cooler sand beneath. And the really hot sand was away from the water where it was very dry…below the high tide line it sometimes got hot but not scorchingly so.
One place I never ever burned my feet no matter how hot it was, was on grass. Or anywhere near the canopy of a tree…even if the canopy extended over the blacktop, and was only dappled and shifting shade…it made all the difference.
Growing plants for a living for many years, and being an avid gardener, I have had many occasions to note the very striking and dramatic microclimates created by structures, paved surfaces, and trees.
Even a small slab of a patio in the middle of a grassy area can be several degrees different from nearby areas. And even a single tree can have a very large cooling affect. Having many trees in an area obviously cool the area.
Dramatic effects from a small structure or paved surface imply larger such effects from large areas of pavement and structures.
Anytime structures are added and/or new paved surfaces are installed, some other surface must be eliminated, and whether it was grass, trees, bushes and hedges, or some combination of those, there is less cooling and more heat retention in that area. And I am not really sure about the UK, but here in the US, air conditioning units are becoming larger and more commonplace. Large buildings are never constructed with windows that open anymore…they are all climate controlled year round. This adds even more heat to the exterior space around structures. So add that in to the mix as airport traffic increases year by year, and more structures are added near these centers of commerce, shipping, and transportation.
My apologies that I did not recognize the sarcasm, but I have read far worse from people who were dead serious. In many cases, hard data, often derived from experiences in everyday life, contradicted a warmist’s position. That never seemed to faze them, though.
that heat is traveling some distance.
“The magnitude of the blast to be expected, and updated blast distance figures are needed to fully understand the nature of the danger from today’s jet aircraft. For instance, for a large aircraft like a Boeing 777 taking off, the blast velocity out at about 2,200 feet can still reach 35 MPH”
https://www.copanational.org/PilotsPrimerDec07.cfm
Out of interest, In fig 2, Wittering, Cranwell, Manston, Marham, Waddington and Bradford are all airstrips. The first 4 are active RAF airfields, Manston is inactive, but the met. array is close to the tower, Bradford is a civil airport. I can’t speak for the other sites.
This was interesting..
If the new asphalt on the north runway only made it 2-3 degree hotter…
The measurement would be in line with Kew…and no where near a record, which Kew wasn’t
http://www.carbonbrief.org/media/423125/imagetemp.png
Old asphalt street: soles feel warm after 50 sec. Measured 141 deg F
New asphalt parking lot: soles feel hot after 20 sec. Measured 162 deg F
http://climateaudit.org/2007/07/27/asphalt/
Fascinating graph. The whole peak temp lasts a few minutes, and the excursion from the linearly decreasing trend is less than 30 minutes. This is why I simply can’t get my head around the practice (obsession?) with averaging high and low temperatures to get some meaningful information about a day’s heat content. Yes, it was hot for 20 minutes–what about the rest of the hour, day, week, month?
When observations were limited by the ability of a human to look at a thermometer, yielding sparse data, this sort of averaging made sense. But with continuous recording as above generating a complete time series, it’s pretty meaningless to focus on highs and lows. There has to be a better way of describing the heat content. I’ve been impressed, for example, by the general observation of higher low temperatures while high temps are essentially unchanged in much of the record. An averaged high and low dispenses with even that small detail present in the information.
Nutty to get excited about one station’s 20 minutes of fame.
I think I remember reading somewhere quite recently that Heathrow only began measuring the temperature in 1948. If this is correct then the hottest day ever should read ‘since 1948’ Can anyone confirm this?
Tony Windsor
That is when the Met, Office data starts;
http://www.metoffice.gov.uk/pub/data/weather/uk/climate/stationdata/heathrowdata.txt
Thank you for that! Does this snippett of information influence the discussion? the Met Office, so far as I recall, make no mention of the time line. 66 years of stats is interesting; how does this compare with the CET?
If I stand in a plume of jet exhaust, any day could be the hottest day on record.
@ur momisugly AP,” If I stand in a plume of jet exhaust, any day could be the hottest day on record.”
I doubt you’d be around for the whole day!
Not sure what you mean.
Monthly CET data goes back to 1659, but there’s apparently no Heathrow data to compare with that.
Couple of points. Most of the met stations quoted here are airports. But mostly minor or RAF fields, so less traffic and therefore less heat.
As to your heat calculations, please remember that a jet will burn the most when it is not moving, and burns less and less as it get some airspeed, which supercharges the engine.
So a 747 on take off will be burning an increadible 100 tonnes per hour, during the take-off roll. Obviously this will reduce down to something like 28 tonnes an hour in the cruise. So the greatest fuel burn, is not up to 3,000 ft — it is on the runway itself.
Ralph
Silver ralph July 18, 2015 at 2:14 pm
“So a 747 on take off will be burning an increadible 100 tonnes per hour, during the take-off roll. Obviously this will reduce down to something like 28 tonnes an hour in the cruise. ”
Are you sure? They only need around 90 tonnes to get across the Atlantic so at the rates above they would be out of fuel half way across!
[Initial Take-off acceleration is only a few seconds of the entire takeoff roll-liftoff-gain altitude, which is only one-two-6 minutes of the entire takeoff-then-get-to-flight-altitude part of the flight. .mod]
Yes, but 28 tonnes an hour in the cruise for a 7 hour flight to JFK is 196 tonnes, and they only take around 90. I think cruise must be closer to 12/13 tonnes per hour, otherwise at that fuel burn rate 747 would require over 350 tonnes of fuel for its max range flights!
Sorry, I think I have a pound-kilo error.
Max tankage on the 747-400 is 173 metric tonnes at an s.g. of 0.80.
In the cruise, the fuel burn will reduce from about 12 t/hr to 10 t/hr
The large increase in fuel burn on take-off is only for a few minutes, and is normally about 4x cruise. This would equate to about 45 t/hr on the take-off roll. Once the aircraft gets some supercharging speed, the burn quickly comes down to half that.
“They use their engines to move around the airport, blowing hot air out behind them as they go”
There’s been quite a bit of work done on trying to reduce the use of engines during taxying – fuel costs being the main concern. Employing more tugs to take planes to and from the runway is one proposal, but this will obviously cost the airports a lot of money. There may well be other reasons – extra taxiways to enable the tugs to move around – in addition. Electric motors to drive the aircraft’s wheels is the other method, but this adds weight and complexity, and needs the APU to power them, when it might not otherwise be running. But in either case there is the risk of a plane getting to the departure point (with a long queue behind) and then finding a problem with an engine, which would normally have been discovered when the plane was being “pushed back” from the stand. Also, this means the engines may barely have time to get properly warmed up before being asked to provide take-off thrust. I believe some airlines now shut one engine down, as soon as they reach their runway turn off, but this is dependent on knowing which route they will be taking to the stand. Differential thrust is commonly used whilst taxying, and turning away from a “dead engine” can be difficult at low speeds. I doubt that any of this is likely to take place at an extremely busy airport like Heathrow – they simply can’t take the risk of disruption with so many aircraft moving about at the same time.
I think you guys have totally taken your eye off the ball….
You’re coming up with all kinds of reasons to explain the “spike”….but the only reason you are is because the spike is a record…
…go after the record
They repave this airport about every 10 years….
The south runway and it’s parts were paved in new asphalt winter of 2013…summer of 2014 was it’s first summer.
The north runway and all of it’s parts were repaved by the winter of 2014….summer of 2015 was it’s first summer
Summer of 2015 was the first summer that the entire airport has had new black asphalt.
If all that new asphalt only raised the temp around a 1/2 degree….there would be no record at all.
It is important not only to debunk the spike, but also the base-line temperature. Other things to look into:
-Have the terminal buildings been re-fitted recently with more powerful air conditioning?
-Has air traffic increased over time?
-Has there been any changes to the general pattern of ground movements?
-Are there any other large electric motors in the vicinity?
-Has the vegetation cover changed (type, quality etc)?
-Most runways were widened for the introduction of the A380 in around 2005, was this the case at LHR?
I think it is the amount of EU bureaucrats entering and leaving the UK. (all that hot air).
As Latitude showed earlier (by graph) the “spike” lasts about 20 minutes. Doesn’t seem right it would be from a short blast from a jet engine. Also from Latitude’s graph there are many short period changes of +/- 0.5 degrees suggesting the temperature station does not have a long thermal memory.
We took some friends to the Canadian side of Niagara Falls recently. Near the dinosaur mini-golf there is a massive volcano that “erupts” in a fire-ball every few minutes. The fire goes straight up but you can instantly feel the intense heat on your skin. The heat is gone as quickly as the fire show ends.
If the temperature measuring equipment set up at Heathrow takes 20 minutes to re-equilibrate after a jet goes by then we shouldn’t even be analysing those records.
The increase in the 10 year mean difference between Heathrow and CET is 0.96c but averages smooth out the differences. Individual monthly differences (let alone daily or hourly) can be much higher.
The June 2015 mean for Heathrow was 16.8c, whereas CET was 14c, that’s a difference of 2.8c compared to a difference for June 1948 of 1.2c, an increase of 1.6c.
Whichever way you look at it, something is increasing the temperatures at Heathrow relative to CET.
Don’t forget the burning rubber and hot brakes caused by landings.
Also, I would imagine quite a lot of aircraft parked at the terminals/remote stands would be running APUs trying to keep their cabins cool.
They don’t have electric sockets at the terminals?
Without engines or APU running, aircraft need ground support to condition cabin air.
http://www.altramotion.com/~/media/Images/Corporate/NewsRoom%20Images/APImages/mobile-aircraft-air-conditioning-unit.ashx
Many of the big airports have air conditioning units that plug into the aircraft, especially in the south.
The other issue here is the transient response of the modern thermometers which produces a bias towards recording spikes in temperature compared to mercury thermometers.
Willis, you are a genius! But even geniuseseses…make minor mistakes at time. 30% converted “mechanically”. My my, WHAT pre-tell do you think happens to that “mechanical” energy? Yep, it turns into HEAT. Thus the energy released in the local area by the aircraft is ALL expressed as air heating.
Rather than leave it at the airport, I think the airplanes take that mechanical energy with them.
Not when they’re landing on that runway.
Planes carry stuff (passengers, cargo) from one place to another and then back. They tend to be not moving relative to the Earth when passengers come in and out (which means they are actually moving wrt to Earth center of mass, but then they return to the original place).
Overall, they dissipate as heat most of chemical energy they consume (but they also use some energy to lift fuel molecule from airports to 30,000 feet where the fuel atoms are thrown away as CO2 and H2O and other stuff).
The question is “how much is dissipated near airports?”
“30% of the energy is used to produce mechanical work, with the rest lost as heat.”
Yes and no; the mechanical energy is used to accelerate, lift, and move through the air at constant speed. The movement creates drag. The drag creates heat.
Planes use fuel to get kinetic energy, and cross the 3000 feet ceiling with kinetic energy, but other planes cross the same ceiling with kinetic energy and then almost stop on the runway, turning this kinetic into heat through brakes and drag (with the help of spoilers). We would have to compare the speed of a plane at 3000 feet during takeoff and landing.
Of course, planes use fuel to generate lift and go from 0 feet to 3000 feet, but the same planes went the other way (no plane is made or destroyed in the airport). The difference is that of course planes carry more fuel when they do up, so you would have to account for the fuel consumption during the whole above 3000 feet flight. This difference means the planes accumulate more potential energy when they go up than they recover when going down. Also, they have more kinetic energy at the same speed during takeoff.
I would guess most of the mechanical energy produced below 3000 feet is turned into below 3000 feet heat. Some is turned into above 3000 feet heat.
The other thing that would be nice to know, is how their thermometer reacts to transients. If the sensor recieved a short hot burst every five minutes, for a whole hour, would it record a series of spikes, or would it just average them out into one long temperature increase?
So can the Met Office actually identify a jet-blast spike, or not??
I don’t think those other weather stations provided are the greatest “comparison stations”
You can view them all using this tool, google maps, google images, and bing maps.
https://badc.nerc.ac.uk/search/midas_stations/
Here is the top half, not to confidence inspiring.
Wittering, active since 1955 and at an AIRPORT.
St James Park: active since 1903, park in DOWNTOWN LONDON.
Cranwell since 1917. At an AIRPORT. Next to a road and a runway.
Nottingham (watnall) since 1941. Seems like it was rural at one time and is now surrounded by lots of development and asphalt. Next to a PARKING LOT.
Manston. since 1928. At an AIRPORT. It’s in a field situated between the runway and a road. Also, its on a peninsula that juts into the english channel.
Sutton(bonnington) since 1900, right next next to a road, but in a big field. I am not sure though. there is a nearby university, airport and nuclear powerplant.
Stonyhurst is visible in bing maps and not in google maps. It is possible that it MOVED recently.
Can someone tell me why, with all their massive funding, Met has never set up a system of pristine weather stations.
The US did it in 2005, (and that system shows cooling), and the UK is much smaller.
Don’t they want “clean” data ?
Is it that they knew they would need these dodgy airport and inner city weather stations to actually create some warming?
>>believe some airlines now shut one engine down,
>>as soon as they reach their runway turn off,
Yeah, some brain-dead flight managers insist on this. Yes, they save 20kg of fuel each flight, but they also scrub out a $4,000 set of nosewheel tyres in half the normal time. Yippooo, what a stupid victory.
>>30% converted to mechanical….
>>what happens to that mechanical energy
Actually, Willis is right. The ‘mechanical energy’ becomes kinetic energy and potential energy. If this energy is released back to the environment as heat, it will be in JFK or DCA, not LHR.
Ralph
Are you saying planes go to JFK and DCA, but not from these places?
The temperature spike was at LHR, not JFK…. 😉
There must be a big pile of used planes at the end of the runways at JFK and DCA.
The temperature spike was at LHR, not JFK…. 😉
An aircraft going from stationary on the ground to 170 knots and 1000 feet above ground level 60 seconds later seem like a lot of work/heat. On landing all that energy is dissipated with work/heat. These acceleration/decelerations and height changes would seem to create additional heat.
>>Stonyhurst is visible in bing maps .
>>It is possible that it MOVED recently.
Stonyhurst is one of the few good monitoring stations – an old monastery and now a college. It replaced Ringway (ie Manchester International Airport) a few years back, as a part of the CET temperature record.
Stonyhurst is famed for having the oldest temperature record in the world.
Ralph
There are 2 pictures of stonyhurst one from google earth and one from bing. I think the station moved, since it doesn’t show up in the google picture.
I could be wrong. I just have a bad image from google maps that doesn’t seem to show the station.
If you really wanted to find out the impact you’d scatter 40 or 50 thermometers around LHR and the mile or so around it, even just for three months, sampling no less than every five seconds, and plot the anomalies against location and takeoff/landing activity.
Based on commodity Arduino-grade microcontrollers these things ought to cost $125 each, and I’d postulate that you’ll see enormous fluctuations between locations and, at certain locations, even between samples on occasion.
Very good post, and some great comments. Paul Homewood was on this, Christopher Booker put it into the MSM, and thanks to Judith you have boiled it down in a nice figuration. The UK Met is revealed to be an incompetent PR engine. Another hole below the CAGW ship of state waterline.
Aircraft Plumes
Detecting hot engine plume temperature
I wonder if there are any satelite IR images of airports?
See Google Images: Satellite infrared imagery airports