Hottest Ever? Really?
Last week the UK was even hotter than the summer of 1976, or at least that is what the Met Office keeps telling us. Is that really the case though?
It has certainly been extremely hot the last few days. We have been inundated with daily claims of new temperature records being set, forecasts that temperatures could even get close to 40C (they did not) and the obligatory red heat warnings informing us we might die if we step outside our front doors.
But where is the evidence that this heatwave was even worse than in 1976? Most people who remember the 1970s would probably say the Met Office is gaslighting us.
In 1976, temperatures hit 35.9C in Cheltenham on 3rd July. The Met Office reckons that this temperature was exceeded last week.
Top of the list are Lingwood and Santon Downham, both in Norfolk, which they say recorded 37.7C and 37.3C on Friday, a new record for June. Santon Downham in Norfolk is, however, one of the most poorly sited weather stations in the country, even by the Met Office’s abysmal standards. It is a Class 5 site, the worst category, which the World Meteorological Organization (WMO) says can add up 5C of artificial warming because of siting issues. In other words, the temperature at Santon Downham might have been as low as 32.3C if it had been properly sited.
Lingwood, another Class 5, is even worse. It is just a few yards away from a thick bank of trees and surrounded on the other three sides by tall hedges. It is a perfect sun trap, as there is no air circulation.
Class 5s mop up all the stations that don’t meet the criteria to be a Class 4, itself a junk classification. The WMO is absolutely clear – Class 5 sites should not be used for climatological purposes, which is exactly what the Met Office have done here.
Just behind Santon Downham came RAF Wattisham in Suffolk. It is actually now used as an Army helicopter base, flying Apaches. Wattisham, as with all airfield sites, is criss-crossed with runways, but it is also home to 2000 troops, 300 HGVs, 200 Land Rovers and two Air Ambulances. Hardly a suitable rural site!
On the Thursday, the two highest temperatures were set at RAF Merryfield and RAF Yeovilton, two Royal Navy helicopter airbases close together in Somerset. The latter is described by the Navy as “one of the busiest military airfields in the UK”.
Maybe you are seeing a pattern here! The day before, on the Wednesday, the Met Office claimed a new June record of 36.1C in Gosport, at, you guessed it, yet another helicopter airbase.
It says a lot about the predominance of junk sites in the Met Office’s station network. It also says a lot about helicopters. We are familiar with the artificial warming effect of tarmac runways, but helicopters add another factor – rotor wash. In essence, the rotors push the air downwards during take off and landing, and that air includes hot exhaust gases. When this air hits the ground, it spreads outward in all directions, creating winds that can easily reach 60 to 100 mph. An excellent way, therefore, of spreading hot air around the airfield.
It is well accepted that thermometers at airfields are there so that pilots know the actual conditions on the runway and should never be used as being representative of the wider area.
In fact, no pristine weather station beat the 1976 record of 35.9C. The Met Office claims of record temperatures are wholly derived from junk sites.
The highest temperature recorded last week at a Class1 site was 34.3C at Rothamsted. This was a degree higher than in 1976 there. But here we have another problem – we are not comparing like with like.
The two different thermometers sit side-by-side in a Stevenson Screen, this example is at Wagga Wagga airport, NSW. Photo: Bill Johnston.
In 1976, all thermometers were of the traditional Liquid in Glass type – the sort that we look at every morning in our hallway! During the 1990s, these were steadily replaced by Platinum Resistance Thermometers (PRTs), which record temperatures on a second-by-second basis. Nowadays all Met Office weather stations use PRTs.
PRTs can detect short term spikes in temperatures which the old thermometers were incapable of. Research has shown that these spikes can be a degree or more, and are more common at poorly sited stations.
We simply cannot scientifically compare temperature data from 1976 with today’s, as the equipment was different then.
Much of this is counting angels on the head of a pin. But a look at the daily Central England Temperature should convince anybody still dubious about which was the hotter heatwave.
In 1976, temperatures exceeded 29C every day from 25th June to 8th July – that’s fourteen days in all. This time, the heat lasted just four days – Tuesday to Friday. As of writing, temperatures are back to normal and are forecast to stay so.
Even the peak temperature in 1976 was slightly higher – 33.1C v 32.8C.
This whole saga is a reminder of how worthless the Met Office’s temperature datasets have now become.
source notalotofpeopleknowthat.wordpress.com
Tom
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These temperature comparisons are quite inane unless you have maybe 100,000 years of high quality data to compare against. Using 150-200 years of data (some of it questionable) is beyond stupid and has absolutely no meaning. Also where and when a reading is taken matters quite a lot. In some instances, readings might be higher depending on the surfaces nearby that are heat reflective. Besides, all this nonsense about record heat waves is silly since almost twice as many people die from the cold than from the heat. When you see a glacier heading in your direction, then you can become worried.
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Charles Higley
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Ah, it’s more like 8 to 10 times more people die of cold rather than heat.
For J O’Sullivan: what’s with the row of six blocks taking up the bottom of my window here? 3/4th of an inch high. It’s annoying and limits the viewing space. Can I get rid of them or do you have to do/move (a drop down?) it?
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John O'Sullivan
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Hi Charles, the articles have an ad at the end which can be clicked off via the x in the right side corner. I think that’s what you refer to
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Charles Higley
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The hot summer of 1976 is a great example of atmospheric blocking by the jet stream which can lock in hot and cold regions for 1 to 3 months. This is typical of a cooling planet and 1976 was part of the current-at-the-time cooling cycle of the planet. It also goes to show that global warming is not needed for heatwaves, particularly as the current heatwave in the UK is during the atmospheric blocking of a COOLING cycle.
We have to ignore the spurious and erroneous temperatures reported by the MET, which loves to pull data from non-existent and low grade temperature monitoring sites and then alter the data, if needed, to increase the warming to report.
In the 1970s, in Maine on an island, we spent a summer under the blocked jet stream and had constant fog for 10 weeks. The next summer we were in a hot meander region of the jet stream, had no rain all summer, and 12,000,000 chicken died from the heat on the Maine mainland.
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D. Boss
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I’m glad you indicated that airport weather stations are entirely fit for the purpose of providing aircraft safety, as the precise condition of the air is critical for aircraft operations at an airfield. They are not fit for climate analysis purpose, as they typically read a degree or two higher than the surrounding terrain.
However the continued guessing nonsense about aircraft exhaust or here helicopter rotor downwash and outwash is simply without merit. Looking at RNAS Yeovilton, it has an area of 550 acres with a polygon encompassing all the runways and aprons. Let us look at some actual numbers for this base, and the main helicopter type flown there.
The base has from 50-150 movements per day, that is, take offs and landings of helicopters. And being a military base, we can assume it operates 24 hrs per day. So from 2.1 to 6.25 movements per hour. Hmm, not much air traffic, really…
Right now the wind at this airbase is from 300 degrees at 10 knots. 10 knots is 5.14 m/s. If we draw a line perpendicular to the wind, extending from the long runway end to the west and to the north end of the short runway, it is 1700 meters. Take 10 m height and multiply by the wind speed of 5.14 m/s we get a wind flow volume across the airfield of 87,380 cubic meters per second. That’s a lot of airflow into which is mixed any turbine engine exhaust, or rotor down and out wash.
Now the weather station is clearly visible in Google Earth, located in the grass between the intersecting runways and the apron. It is 160 meters from the apron and closest to either taxiways or runways is 100 meters.
The principle helicopter is the AW159. It has a rotor diameter of 12.8 meters and it produces a downwash of 13.7 m/s and an air volume in that wash of 1760 m³/sec. Hmmm that is pretty small compared to the wind across the airfield…
Now the downwash spreads out to approx 3x rotor diameter in all directions, so an outwash width of 76.8 meters.
The engines of the AW159 produce 2.5 m³/sec of exhaust at roughly 500 degC, but the helicopter has an IRS system (Infrared Reduction System) which mixes ambient air with the exhaust to reduce the IR signature, but the amount of ambient air is classified. Let’s assume it is 10x and this reduces the temp to 100C. So 25 m³/sec at 100C.
If we mix 25 m³/s at 100c with 1760 m³/s at 30C we get a temp of 30.8 C. So the air immediately beneath and around the rotor wash is only 0.8 C warmer than ambient. However the helicopter can never get closer than 100 meters from the weather station and even then if it’s taxiing, the wash only passes the station for a up to 15 seconds (taxi speed is 10 knots). If we add in the wind air volume to the mixing scenario, 100 meters at 5.14 m/s would be 19 seconds of wind volume on this rotor wash path, being roughly 75,000 m³. this reduces the rotor wash temp to 30.02 C – for perhaps 15 seconds, from 2 to 6 times per hour. Even then given the sheer size of the airfield, the likelihood of a helicopter passing directly upwind of the weather station is minimal, perhaps 98% of the they do not.
The helicopter exhaust/rotor wash argument appears to have no merit! Does the wind air volume passing over the hot concrete affect the weather station? YES. Do the aircraft exhausts from the rotary wing movements substantially affect the weather station? NO.
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