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Aleman

Northolt, Heathrow, Temperature Records and Weather Station Siting

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(Message from Paul)
This thread has been created by splitting out posts from the warmest temperature competition thread, as the ongoing discussions warranted a thread on their own 🙂 

Northholt location - another in an airport probably not fit to be a weather station. Look in tiny gap between giant concrete triangle to N and A40 to S and with very near fence to S and very near trees to E. Needs bulldozing. Can't link unfortunately. French high station location being questioned, too.

 

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9 hours ago, Aleman said:

Northholt location - another in an airport probably not fit to be a weather station. Look in tiny gap between giant concrete triangle to N and A40 to S and with very near fence to S and very near trees to E. Needs bulldozing. Can't link unfortunately. French high station location being questioned, too.

Ah, that old chestnut? I wondered how soon it would be brought up.💤

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11 hours ago, Aleman said:

French high station location being questioned, too.

 

What, all 11 of them?!

 

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Posted (edited)
8 hours ago, Ed Stone said:

Ah, that old chestnut? I wondered how soon it would be brought up.💤

He's right though, several sites on major airports including Heathrow, and some others the subject of urbanization  are open to criticism and always will be. This goes back a long way, I got the Met Office to do an investigation into the old Manchester Airport (Ringway) CET station way back around 1970, due to steadily increasing overnight minima.  It was shown to be urbanization to the north and developments at the site causing that very obvious effect - once they actually examined the data.

It's probably inevitable for practical reasons and I don't pretend to have the answer to it, it's just something to bear in mind as these west London airport stations increasingly report high temperatures. I hope it can be accurately adjusted for in climate modelling.

Edited by DaveL

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Posted (edited)
13 hours ago, Ed Stone said:

Ah, that old chestnut? I wondered how soon it would be brought up.💤


Northolt weather station is only 10m north of a 6 lane A40 AND separate wide cycle path AND a windbreak line of trees beyond that to the south which likely encourages heated eddies to linger from southerlies.(It looks like it used to be twice as far from the road until it was expanded to 6 lanes from 4.) It is partially sheltered from further wind by a line of trees 12-15m high just 15m to the East. Cars park in a line 20m to the north that might on rare occasions reflect southern sun, although I would guess it is not unique in this. In the Northolt Google map, the satellite photo looks to be taken just after a drought and you can see the grass has been baked brown up to 5m on the sides of most runways and a bit more than that from the A40. You can actually see the effect of heating from road and traffic. Across the road to the south is a plant hire business that looks to have turned a green farm field to dust.

I've found a photo here(3rd). The weather station is just across the road from the big puddle in the field. There are photos of this field bare at planting time so the farmer's choices could affect readings slightly during southerlies. There is no grass south of the beck thanks to the plant hire business in later pics.

https://www.mirror.co.uk/news/politics/queens-airport-raf-northolt-shut-11163520

If an amateur set up a station like this for more than casual local use, I think they would draw criticism. It seems too problematic for professional climate monitoring to me, though I'm no expert.

After a lot of Googling, it looks like some have taken issue with Northolt before - Class 3 weather station and not 2 because it's too near tarmac. (Lots of it!) Please note, I've not seen this blog before and have no connection but comments seem valid.

Https://tallbloke.wordpress.com/2012/09/10/wmo03672-northolt/

Is this acceptable to the Met Office for climate monitoring? I appreciate perfection is difficult but this one looks too far from it.

Here's some old pictures and plans to highlight development but not necessarily part of the main criticism:

Http://www.ukairfieldguide.net/airfields/Northolt

Should airport stations be used for climate data analysis when they seem to draw constant development and traffic?

 

(I think this post is relevant to this thread but feel mods might want to point me and this post in the direction of where this debate has cropped up before. I'm curious what the official line might be on terrible siting.)

Edited by Aleman

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Posted (edited)
8 hours ago, Aleman said:


Northolt weather station is only 10m north of a 6 lane A40 AND separate wide cycle path AND a windbreak line of trees beyond that to the south which likely encourages heated eddies to linger from southerlies.(It looks like it used to be twice as far from the road until it was expanded to 6 lanes from 4.) It is partially sheltered from further wind by a line of trees 12-15m high just 15m to the East. Cars park in a line 20m to the north that might on rare occasions reflect southern sun, although I would guess it is not unique in this. In the Northolt Google map, the satellite photo looks to be taken just after a drought and you can see the grass has been baked brown up to 5m on the sides of most runways and a bit more than that from the A40. You can actually see the effect of heating from road and traffic. Across the road to the south is a plant hire business that looks to have turned a green farm field to dust.

I've found a photo here(3rd). The weather station is just across the road from the big puddle in the field. There are photos of this field bare at planting time so the farmer's choices could affect readings slightly during southerlies. There is no grass south of the beck thanks to the plant hire business in later pics.

https://www.mirror.co.uk/news/politics/queens-airport-raf-northolt-shut-11163520

If an amateur set up a station like this for more than casual local use, I think they would draw criticism. It seems too problematic for professional climate monitoring to me, though I'm no expert.

After a lot of Googling, it looks like some have taken issue with Northolt before - Class 3 weather station and not 2 because it's too near tarmac. (Lots of it!) Please note, I've not seen this blog before and have no connection but comments seem valid.

Https://tallbloke.wordpress.com/2012/09/10/wmo03672-northolt/

Is this acceptable to the Met Office for climate monitoring? I appreciate perfection is difficult but this one looks too far from it.

Here's some old pictures and plans to highlight development but not necessarily part of the main criticism:

Http://www.ukairfieldguide.net/airfields/Northolt

Should airport stations be used for climate data analysis when they seem to draw constant development and traffic?

 

(I think this post is relevant to this thread but feel mods might want to point me and this post in the direction of where this debate has cropped up before. I'm curious what the official line might be on terrible siting.)

I guess that's a 'better' argument than the one that was 'wheeled out' following a previous Northolt (or was it Heathrow?) max...that its reading was influenced by heat from an overflying jet engine?:hi:

Edited by Ed Stone

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Is an urban setting not entirely representative of a good part of that part of England though? I'd have thought, in SE England and London in particular, having sites which are solely away from urbanisation would actually give a less accurate and representative picture of the temperatures in that part of the country?

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Posted (edited)
7 hours ago, Paul said:

Is an urban setting not entirely representative of a good part of that part of England though? I'd have thought, in SE England and London in particular, having sites which are solely away from urbanisation would actually give a less accurate and representative picture of the temperatures in that part of the country?

Maybe, but there are two of them close together in an area subject to increasing urbanization and in the case of Heathrow, airport developments. These can and do produce atypical (of the wider area) changes with time, as I mentioned earlier in my comment about the old Manchester Airport CET station. That one was replaced by a more representative station Rostherne no. 2 (though not for the CET which switched to Stonyhurst much further north). I'd have thought St. James's Park is a better 'urban' station for London albeit in a park, and there are others e.g. Kew Gardens.

It would make more sense to my mind if less prominence is given to Heathrow and Northolt especially for record purposes i.e. if they do approach or break records, add a qualifier and always mention the best 'clean' station too. Manchester and Gatwick are fine, as there are off-airfield official stations in the same general area, these days. Same should be done in west London IMO so Heathrow and Northolt don't need to be quoted.

Edited by DaveL

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Posted (edited)
8 hours ago, Paul said:

Is an urban setting not entirely representative of a good part of that part of England though? I'd have thought, in SE England and London in particular, having sites which are solely away from urbanisation would actually give a less accurate and representative picture of the temperatures in that part of the country?

Yes, whether the temps are influenced by man or not is irrelevant, if a thermometer says its 30c and it is 30c, regardless of the reasons its 30c, then its accurate.

Edited by feb1991blizzard

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Posted (edited)
9 hours ago, Paul said:

Is an urban setting not entirely representative of a good part of that part of England though? I'd have thought, in SE England and London in particular, having sites which are solely away from urbanisation would actually give a less accurate and representative picture of the temperatures in that part of the country?

Not really. That's the problem.  "Urban setting" is a very vague term. Temperature varies tremendously over short distances and with local environmental changes and nowhere is the same as anywhere else. (Remember the car that melted in front of the "Walkie Talkie".) You need to standardise measurement so everyone understands what is being measured  to get a reading that represents anything. It would be a step forward if we were told Northolt was the hottest place on a particular day but, using that bloggers terminology, it's effectively a class 3 site that used to be a class 2 and maybe even previously a class 1 so it might not tell us anything about wider Northolt or indicate anything about climate. We have a hot temperature. Yes, it is that hot, but there might be a traffic jam making it that hot, which tells us not a lot. To tell us anything from which we could draw conclusions, we need standardisation, which means siting to remove (as much) local interference (as possible) and trying then to keep nearby development/clearance/changes to a minimum such that local influences are hopefully close to negligible. I think it is fair to say Northolt has probably failed in that. It's the worst siting I've seen. It did not even look good in the 50s and looks worse now.

Thanks for sensible responses.

Edited by Aleman

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On 02/07/2019 at 03:49, Paul said:

Is an urban setting not entirely representative of a good part of that part of England though? I'd have thought, in SE England and London in particular, having sites which are solely away from urbanisation would actually give a less accurate and representative picture of the temperatures in that part of the country?

The vast majority of the south-east outside of London is most certainly not urban.

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Posted (edited)
19 hours ago, feb1991blizzard said:

Yes, whether the temps are influenced by man or not is irrelevant, if a thermometer says its 30c and it is 30c, regardless of the reasons its 30c, then its accurate.

In that case then we might as well just stick weather stations in city locations covered in tarmac - then we could all enjoy a flurry of obscene weather records in the years ahead 😅

Edited by Relativistic

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21 minutes ago, Relativistic said:

In that case then we might as well just stick weather stations in city locations covered in tarmac - then we could all enjoy a flurry of obscene weather records in the years ahead 😅

In 1000 years time maybe yeas, as that would accurately reflect most of the landmass with population explosion and net migration at 300000 a year.

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On 01/07/2019 at 23:48, Aleman said:

Should airport stations be used for climate data analysis when they seem to draw constant development and traffic?

...

(I think this post is relevant to this thread but feel mods might want to point me and this post in the direction of where this debate has cropped up before. I'm curious what the official line might be on terrible siting.)

In view of the subsequent interesting discussion I too wonder if the relevant posts could be moved into a separate thread for further comments and maybe examples of other 'dubious' weather stations? I know of a few.  There may already be a thread somewhere, apologies to all if there is!

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1 hour ago, DaveL said:

In view of the subsequent interesting discussion I too wonder if the relevant posts could be moved into a separate thread for further comments and maybe examples of other 'dubious' weather stations? I know of a few.  There may already be a thread somewhere, apologies to all if there is!

There's almost certainly something in the archives, Dave...as the UK's climate continues to warm, there are more and more 'questionable' records to choose from.:oldgood:

I seem to remember that the nonsense known as 'Climategate' was based on similar beliefs. Only, in that case, it was air-con systems that were to 'blame'...Allegedly?:oldgrin:

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I think the reason this topic triggers so much discussion is due to the ambiguity of the meaningfulness of the readings, i.e. how does one interpret them? "How much" of a new record do we assign to urbanisation and "how much" do we assign to climate change? With stations like Heathrow and Northolt those questions are very difficult to answer.

 

If we were to close these stations then I have no doubt we would find others to moan about.

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23 minutes ago, Relativistic said:

I think the reason this topic triggers so much discussion is due to the ambiguity of the meaningfulness of the readings, i.e. how does one interpret them? "How much" of a new record do we assign to urbanisation and "how much" do we assign to climate change? With stations like Heathrow and Northolt those questions are very difficult to answer.

 

If we were to close these stations then I have no doubt we would find others to moan about.

Given that we in the UK usually only get the 'leftovers' from already record-breaking European heat, I'd suspect that the vagaries of individual recording-stations like Heathrow and Northolt have little to do with it?

The rolling 30-year mean just keeps going forever upward...

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Posted (edited)
3 hours ago, Ed Stone said:

Given that we in the UK usually only get the 'leftovers' from already record-breaking European heat, I'd suspect that the vagaries of individual recording-stations like Heathrow and Northolt have little to do with it?

The rolling 30-year mean just keeps going forever upward...

Aye, that's true in the wider context. But when looking at individual  "ultra-high" readings at such locations folk will always be curious as to how much was due to the local climate (which may be influenced by infrastructure) and how much reflects the current large-scale climatic state. Ergo discussion (... and, for some, bickering!).

Edited by Relativistic

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Posted (edited)
4 hours ago, Ed Stone said:

Given that we in the UK usually only get the 'leftovers' from already record-breaking European heat, I'd suspect that the vagaries of individual recording-stations like Heathrow and Northolt have little to do with it?

The rolling 30-year mean just keeps going forever upward...

The problem is too many stations now have "vagaries" because of constant encroachment that would cause the rolling mean to creep up. How much increase is climate change and how much increase is encroachment? After repeated complaints about weather stations with poor sitings in the US being used as contaminated data sourcing for climate purposes, they created a new network that was picked to be free of distorting influences now and expected to be so over the next 50 years to generate a set of data that will reflect climate better.

https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/us-climate-reference-network-uscrn

I'm not aware that we have such a "clean" network in the UK. The USCRN seems to show no trend as yet after 14+ years. It will be a while before we get a 30-year rolling average for it - and perhaps a lot longer for a UK equivalent!

clip_image008-4.jpg

 

Edited by Aleman

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29 minutes ago, Aleman said:

The problem is too many stations now have "vagaries" because of constant encroachment that would cause the rolling mean to creep up. How much increase is climate change and how much increase is encroachment? After repeated complaints about weather stations with poor sitings in the US being used as contaminated data sourcing for climate purposes, they created a new network that was picked to be free of distorting influences now and expected to be so over the next 50 years to generate a set of data that will reflect climate better.

https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/us-climate-reference-network-uscrn

I'm not aware that we have such a "clean" network in the UK. The USCRN seems to show no trend as yet after 14+ years. It will be a while before we get a 30-year rolling average for it - and perhaps a lot longer for a UK equivalent!

clip_image008-4.jpg

 

You mean they sifted-out all the ones that didn't tell them what they wanted to hear, leaving behind all the ones that did...and, lo-and-behold, the globe isn't really warming after all?

Tell that to all the plant and animal species that keep moving polewards, then? I'm sure they'll be pleased at having their respective biases corrected?

Apologies if I'm Being a wee bit over-sceptical, but I think I've heard it all before...

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They are new stations so can't be cherry-picked on previous performance.

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Posted (edited)
On 30/10/2018 at 10:19, Quicksilver1989 said:

There are issues with coverage and biases in SST (which incidentally are strongly negative) in earlier years but the uncertainties account for this. We have been here before with Berkeley investigating the global temperature record themselves.

Anthony Watts said that:

'.. I’m prepared to accept whatever result they produce, even if it proves my premise wrong. I’m taking this bold step because the method has promise. So let’s not pay attention to the little yippers who want to tear it down before they even see the results.' 

https://wattsupwiththat.com/2011/03/06/briggs-on-berkeleys-best-plus-my-thoughts-from-my-visit-there/

Yet the global temperature dataset created by Berkeley agreed very strongly with the other global temperature datasets and no inhomogeneities through urbanization are evident. Anthony Watts went very quiet after this.

image.thumb.png.59fa73e9fdb720899fc572aa5a9cbb0f.pngimage.thumb.png.1d7e0af2753be7a2aad0e51a9c7309db.png 



 

Sigh the issue of urbanisation has been covered exhaustively by many climate studies, most notably the Berekeley climate dataset, which specifically looked at the effects of urbanisation on the global climate record... here is an earlier post about it at the top.

2 hours ago, Aleman said:

The problem is too many stations now have "vagaries" because of constant encroachment that would cause the rolling mean to creep up. How much increase is climate change and how much increase is encroachment? After repeated complaints about weather stations with poor sitings in the US being used as contaminated data sourcing for climate purposes, they created a new network that was picked to be free of distorting influences now and expected to be so over the next 50 years to generate a set of data that will reflect climate better.

https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/us-climate-reference-network-uscrn

I'm not aware that we have such a "clean" network in the UK. The USCRN seems to show no trend as yet after 14+ years. It will be a while before we get a 30-year rolling average for it - and perhaps a lot longer for a UK equivalent!

clip_image008-4.jpg

 

 

Edited by Quicksilver1989

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Posted (edited)

The "sigh" does not help. I did ask if the problem with UK sites had been discussed on one of these threads and you have linked to something that seems to be a slightly different topic. I can see you are trying to help but what you have posted might need a little more explanation if it is relevant as I don't see what it does to improve and standardise UK sites. I thought our stations were better than some of the US howlers but I'm not so sure now after looking at Northolt.

General urbanisation/heat island effects and encroachment are not the same thing. Having seen Northolt, I'd like to know more about encroachment and site consistency. Warming from a growing city is a real thing to be measured. It IS a small part of the global temperature make-up. But it is not a genuine conclusion from a station if the road next to that station has doubled in size and moved closer, windbreaks have changed, the type of temperature sensor has changed  and ageing equipment or poor maintenance has not been accounted for. At least the USCRN recognises these failings and attempts to address them.

Doesn't BEST just reanalyse old stations output? I thought everyone was applying different adjustments for a host of factors and then arguing about it so BEST was more about getting everyone together to harmonise adjustments - adjustments we should be trying to avoid in the first place. Do please correct me if I'm wrong. The USCRN idea to eliminate adjustments for anything (encroachment, urbanisation, maintenance. whatever),  by designing them out at the start so that output would be used without adjustment (if that is possible), seems a better approach and one I would hope everyone would try replicate.  Using the likes of Northolt for climate data - or just media climate headlines - seems negligent from what I can see of it online. I do hope we have no other stations nearly as bad.

Edit - I see Northolt was the hottest Met Station in the UK again yesterday.  But does that make the area around Northolt Airport the hottest or is it just that  Northolt station has become one of the most badly sited/encroached upon since it was built?

Edited by Aleman

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31 minutes ago, Aleman said:

Edit - I see Northolt was the hottest Met Station in the UK again yesterday.  But does that make the area around Northolt Airport the hottest or is it just that  Northolt station has become one of the most badly sited/encroached upon since it was built?

Was actually heathrow yesterday 🙂 

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5 hours ago, Aleman said:

The "sigh" does not help. I did ask if the problem with UK sites had been discussed on one of these threads and you have linked to something that seems to be a slightly different topic. I can see you are trying to help but what you have posted might need a little more explanation if it is relevant as I don't see what it does to improve and standardise UK sites. I thought our stations were better than some of the US howlers but I'm not so sure now after looking at Northolt.

General urbanisation/heat island effects and encroachment are not the same thing. Having seen Northolt, I'd like to know more about encroachment and site consistency. Warming from a growing city is a real thing to be measured. It IS a small part of the global temperature make-up. But it is not a genuine conclusion from a station if the road next to that station has doubled in size and moved closer, windbreaks have changed, the type of temperature sensor has changed  and ageing equipment or poor maintenance has not been accounted for. At least the USCRN recognises these failings and attempts to address them.

Doesn't BEST just reanalyse old stations output? I thought everyone was applying different adjustments for a host of factors and then arguing about it so BEST was more about getting everyone together to harmonise adjustments - adjustments we should be trying to avoid in the first place. Do please correct me if I'm wrong. The USCRN idea to eliminate adjustments for anything (encroachment, urbanisation, maintenance. whatever),  by designing them out at the start so that output would be used without adjustment (if that is possible), seems a better approach and one I would hope everyone would try replicate.  Using the likes of Northolt for climate data - or just media climate headlines - seems negligent from what I can see of it online. I do hope we have no other stations nearly as bad.

Edit - I see Northolt was the hottest Met Station in the UK again yesterday.  But does that make the area around Northolt Airport the hottest or is it just that  Northolt station has become one of the most badly sited/encroached upon since it was built?

Sorry and it wasn't specific to your post, it's just that when we see a record breaking heatwave there is always a spate of posts saying things like 'Ah but that French station is next to a motorway' yet the same people would never complain if there was record cold there... and there was also another 12 stations nearby that also broke the national record.

I may have misinterpreted your post in which case I do apologise. The analysis from BEST was primarily concerned with the potential impact of urbanisation and their series which focused on sites away from urban areas produced exactly the same anomalies as those from the already established land temperature datasets.

As for the quality of the stations, do you have any evidence that they are poorly maintained? I remember Heathrow was singled out during during the July 2015 heatwave but this was comprehensively debunked by the solar radiation data which showed a peak around 14.13 on July 1st when the record was broken.

https://www.carbonbrief.org/met-office-wind-data-dispels-doubt-about-cause-of-heathrow-high-temperatures

I think topography and geography may also play a big helping hand here as well, I just find it curious that everyone jumps onto these record values when the discussions have taken place many times beforehand. Heathrow and Northolt have always been in places that favour higher maximum temperatures.

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